A B737-300 Captain reported difficulty complying with the GEELA 4 RNAV arrival to PHX due primarily to numerous airspeed assignments and revised altitude clearances. On final approach it was discovered that the Captain's altimeter was not set to local and the descent and approach checklists had not been accomplished.

Narrative

On hand off to ABQ Center from LAX Center on the GEELA 4 we began to receive numerous airspeed assignments and revised altitude clearances. We ended up at 260 KIAS and were cleared in multiple step downs to 17;000. During this the FMC seemed to be responding more slowly after every speed change was entered; in particular the autothrottles were slow to respond to the new path. Just after crossing LZIRD we were told to descend via the GEELA 4 Runway 25L. Because of the step downs we were above the profile and I advised the Controller that we would be high over HYDRR. The Controller gave us relief on that altitude and said we were fine 'as long as we made the 12;000/250 KIAS restriction at GEELA. There is no published restriction like that for GEELA. There has been a NOTAM for several months now to cross GEELA at or below 16;000 at 250 KIAS. (I do not understand why this has not shown up on the plates.) The Controller was extremely busy so there really wasn't a good opportunity to query him about the clearance. We saw that we could make the restriction with use of spoilers and so complied with the clearance. (Left to its own devices the VNAV path normally crosses GEELA at around 12;500 FT.) Also at this point the autothrottles failed to respond appropriately to for the VNAV path and we had to disconnect autothrottles; come out of VNAV and use Level Three automation; requiring a reset of the MCP altitude to protect the next fix. At that point we were handed off to PHX Approach; who continued to issue further speed reductions. The task loading did not let up until about an eight mile final with hand off to PHX Tower. At that point I noticed that the landing lights were not on and that my altimeter was set at 29.92. The First Officer's (pilot flying) was set correctly at 30.18. It was apparent that we had not done the Descent/Approach checklist. I followed by ensuring lights; autobrake; and other items were set correctly. Landing was uneventful. The First Officer and I spoke about the event afterward and we concluded that the multiple speed changes; step down altitudes and a clearance to descend via right at FL180 task-loaded us to the point where we missed the checklist.1. The optimum descent profiles work very well as long as the automation is allowed to fly it without interruption. The more often ATC adjusts speed and/or altitude the more likely the opportunity for error. Task loading under these circumstances triples. Some arrivals are more tolerant of this than others. The GEELA 4 for some reason seems to be the most difficult when receiving multiple speed adjustments. A vector off the arrival and then back on seems to work better than constantly adjusting the speeds. 2. This was leg five of a long day. Neither of us was as sharp as were on leg one. 3. For reasons I do not understand; the FMC interface with auto throttles seems to be less robust with update 10.7 than it was with update 10.5.A revision of the GEELA 4 might be in order. Based on the number of times I personally have flown it without speed adjustments I don't think it works well at all for ATC. Also; if there is an altitude and speed restriction regularly used on an approach; that information belongs ON THE PLATE; not as local knowledge or as a NOTAM. We probably should watch 10.7 equipped airplanes for a while to see if there is some underlying issue. I have seen all our airplanes 'act up' to a certain extent; but today this aircraft warranted a write-up..